Seas Idunn 2-Way Speaker Kit - Pair

Seas Prestige Idunn Speaker Kit – Pair – Parts Only

Price shown is for a PAIR

Idunn Kit PDF

The Idunn is a high end 2-Way speaker kit from the Seas Prestige line of drivers. This kit was designed by the Seas R&D team in Norway and utilizes two uniquely advanced drivers in a bass reflex enclosure. Full documentation on the Idunn can be found at the Seas website. 

Drivers

The tweeter is the 27TBCD/GB-DXT (H1499) which utilizes a 1” High Definition aluminum/magnesium alloy dome with DXT lens. This special tweeter solves many issues inherent with loudspeaker design offering improved directivity control, off-axis response, baffle diffractions, and integration with midbass drivers. The woofer is the U18RNX/P (H1571) featuring the new Curv cone. This woven polypropylene with excellent internal damping combined with perfectly matched moving parts gives a smooth, extended frequency response.

Crossover Design

The crossover is symmetrical with a 2.2kHz crossover frequency. The crossover point was chosen so that the directivity of the drivers make the overall power response extremely smooth, as can be seen in the measurements below. Complexity of the crossover was held as low as possible without sacrificing any audible performance. This is possible to achieve because of the response characteristics of these drivers. On the woofer there is a simple 2nd order network, and on the tweeter there is an equally simple 3rd order network with an L-pad to trim the tweeter sensitivity. Together they align the phase of the drivers in excellent fashion and provide a seamless interdriver transition. The rolloff of the drivers is steep enough to allow them to work effortlessly, even at high power levels. The result is detailed sound quality at all levels while maintaining as dynamic a loudspeaker as possible.

Professionally Assembled Crossovers

Each Idunn kit includes two professionally assembled crossovers on 103B printed circuit boards. All parts values are of high quality and an excellent match to the drivers used in this kit. While we always recommend soldering your connections, it is possible to attach all wires to the crossover and drivers using Quick Connects.

The tweeter features ClarityCap CSA capacitors in the series circuit (please note the picture depics the older style SA capacitors). The attenuation circuit uses Mundorf MOX resistors and the parallel coil is a Madisound Air Core.

The woofer circuit features a Sidewinder 16 AWG coil in series and a Bennic polypropylene capacitor in parallel.

Crossover upgrades are available for both the tweeter and woofer section. The caps in the tweeter circuit can be upgraded to the brand of your choice, and the coil in the woofer circuit can be upgraded to a Mundorf Flat Foil 16AWG. These upgrade options are available from the dropdown menu. If there is a specific combination of parts that you would prefer instead, please call or email us.

Enclosure and Stuffing

Enclosure Plans Link

The Idunn loudspeaker is based on a 0.70 cubic foot (20 liter) vented cabinet measuring 9" wide x 21" tall x 11" deep. It is important to keep the driver spacing, baffle width and internal volume of the enclosure to spec when building your own enclosure. Adding braces to stiffen the cabinet is a good tip for the advanced builder to take this loudspeaker just a little bit further.

The amount of stuffing and port tuning is based on measurements and extensive listening. The cabinet is filled with 0.55 lb Acousta-Stuf. The stuffing is distributed evenly in the box, but kept away from the port opening to allow free movement of air. This also ensures that potential air flow noise is as low as possible. The port is 2” internal diameter with an overall length of 6.75” including both inside and outside flares. The 2FLARE Precision Port is perfect for this application. This gives a port tuning of 38Hz, providing a smooth low frequency roll-off.

Each Idunn Kit Includes:

• (2) SEAS Prestige 27TBCD/GB-DXT (H1499) Tweeter 1” Al/Mg alloy dome with DXT® lens
• (2) Seas Prestige U18RNX/P (H1571) 7" Curv Cone Woofer
• (2) Assembled Crossovers - as pictured and described.

You may also choose to purchase the optional accessories package. The accessories package is offered at a discounted price, and will provide you with all the miscellaneous speaker building parts that you need to complete your kit. It is highly recommended that you purchase this accessories package if you do not already have your own stock of parts.

Optional Accessories Package Includes:

• (2) 2FLARE 2” Precision Flared Ports (cut middle piece to 1.75" long)
• (14ft) Supra Classic 1.6 tinned oxygen free copper internal speaker wire
• (1.1lb) Acousta-Stuff fluff & loosely fill cabinet (do not block port opening)
• (8ft) Foam gasket tape - for airtight seal of drivers to cabinet
• (2R & 2B) QC110 Quick Connects - for tweeter tabs
• (8R & 8B) QCC187 Quick Connects - for woofer and crossover tabs
• (20) Screw Size 8, 1" Phillips Pan Head, Black Ox & Wax Finish mount drivers to baffle
• (20) Screw Size 6, 3/4" Phillips Oval Head, Black Ox & Wax alternative to socket head
• (1pc) Kester 3% Silver Solder solder internal wire to drivers/crossovers
• Input Cups or Binding Posts are NOT included with this package since every builder has their own preference. Consider adding some to your order if you don't already have them.

Kit pricing shown includes a discount on all drivers and accessories package. Crossovers are available for seperate purchase from the drop down menu.

Single or odd numbers of this kit are available for 1/2 the price of the pair. Call or write us a note in the "comments" section of your order to request this.

Comment from Seas on the Idunn Speaker Kit

"The Idunn is one of my favorite loudspeakers, and they have been anchored in my living room for a long time now. It has a very neutral and detailed sound, but is still lively enough to get your foot tapping and listen to music for hours. Although, what really separates the Idunn from other speakers, is the controlled wide dispersion. This makes it sound good even outside the sweet spot, when I’m lying in the sofa reading a book, or jumping around the living room." Håvard Sollien, SEAS R&D Manager

Measurements

The measurements are taken in free field at 1metre on tweeter axis.

As seen in the figure the average sensitivity is 85dB and the response lies within ± 1.5dB. The black curve shows the response with the tweeter connected with opposite polarity. The deep and symmetrical notch, when the tweeter is connected with inverse polarity, shows that the drivers are in-phase across the whole crossover region.

The off-axis response of the Idunn is shown above. Here we really see the beauty of the DXT tweeter. The power response is perfectly smooth throughout the entire frequency range even at 60 off-axis. This gives a huge sweet spot, while still allowing for pin-point imaging. It also keeps the tonal balance of the loudspeaker all over the listening room.

The figure below shows the 2nd and 3rd order harmonic distortion with an output of 96dB at 1m. The overall distortion is very low and makes the reproduced music very clean and without coloration.

Professionally Assembled Crossover (Please note that current crossover comes standard with the newest generation higher end ClarityCap CSA line, not the older SA line pictured)